Conventionally, research into the use of oxidation by an oxygen-containing gas for the treatment of liquid wastes containing cyanide focused on the elimination of the cyanide and did not include methods of recovering any dissolved metal from the oxidized waste. Using the conditions of the prior art, oxidation of the cyanide in solution by an oxygen-containing gas produced carbon dioxide and ammonium which would further react with dissolved metal ions present in the liquid to form metal ammonium complexes. Disposal or recovery for further use of these dissolved complexes is difficult. Therefore, the use of the oxidation methods of the prior art eliminate the possibility of reusing metals present in liquid waste and also create additional waste elimination problems.